Raphanobrassica is classical example of allopolyploids. This was produced by a Russian Scientist Karpachenko (1927). He crossed Raphanus lativus and Brassica oleracea and obtained F1 hybrid which was completely sterile. The sterility was due to complete non homology between the genomes of Raphanus and Brassica. But some plants of Raphanobrassica were fertile obviously due to the doubling of the chromosomes.